Follow Marine Biologist Carl Safina as he takes viewers around the world to show us how today's ocean issues are being solved in his PBS series "Saving the Ocean." You can watch full episodes online at the PBS website. Here at A/J he's giving us a behind the scenes look at each episode.

In the 1990s the beautiful and otherworldly fish lionfish, started showing up in south Florida and the Caribbean. Lionfish are native to the west Pacific, Indian Ocean, and Red Sea. Lionfish are here in the Atlantic, it seems, because of owners of living room aquariums who tired of the upkeep and let them “go.”

They now live in plague-like numbers from the northeastern South America to New York. It may see odd to complain about abundance. But invaders from afar often crowd out or gobble a wide array of desirable natives.

No native fish in the Atlantic looks like them, hunts like them, or stings like them. Result: No native fish in the Atlantic recognizes them as a predator. No native fish in the Atlantic gets alarmed when lionfish are on the “hunt,” because a hunting lionfish looks like a drifting piece of seaweed. And no native predator – sharks, say, or barracuda – wants anything to do with their many venomous spines.

And so, there are millions. And they eat. Forty-plus kinds of native fishes have been found in their bellies, including the young of fishes like snappers and groupers and others of commercial, ecological, and culinary value. They eat juvenile surgeonfishes and parrotfishes that, crucially, graze algae off of reefs and make it possible for baby corals to get established and grow.

Atlantic coral reefs are in a world of hurt as is, thanks to new diseases, pollution, silt, overfishing, over-warming, and acidifying seawater. They can’t afford lionfish.

As we found out, if you want to get rid of lionfish, you basically have to remove them one-by one. People are, in fact, organizing groups of spear-fishing divers to do just that. Other people are trying to commercialize lionfish, hoping to make them the next big flash in the pan.

In a derby in Florida that we filmed, divers on roughly two dozen boats competing for prizes killed well over 1,000 lionfish. The only hope is the baddest predator in the sea, whose appetite out-eats all others. Look in the mirror, my friend.

But a derby is just a derby. If invading lionfish are going to be really controlled and their infestation suppressed, it’s going to take a more concerted, commercialized effort. In Florida, I was told that fillets are being sold wholesale for around $12 a pound. In Puerto Morelos, on Mexico’s Yucatan Peninsula, I accompanied fisherwomen in small, open boats.

After making the sign of the cross, one of the fisherwomen grabbed her spear-gun and dove to the bottom in water over 100 feet deep. In about 30 minutes, the diver surfaced with a dozen lionfish worth about $20. They aren’t going to get rich this way. And the diving is also dangerous. Many have trouble with the bends that can eventually disable them (our diver surfaced while our dive computer said she needed to spend 25 more minutes at a depth of 15 feet to safely purge her blood of nitrogen). And then there are those venomous spines. Every one of the spear fisherwomen in our party has been poked at one time or another, taking an excruciating sting. Designing a better mousetrap that can catch quantities of lionfish, even in deep water, would be a needed breakthrough.

Will fishing send lionfish the way of cod, tuna, groupers, snappers, and other overfished ocean wildlife? Before widespread overfishing, Atlantic reefs held enormous numbers of fishes of dozens of species. Lionfish may be, in that sense, the incarnation of all the other fish we’ve already eaten. How they’re overdoing it just might reflect, at least in part, how we’ve overdone it.

It’s a sad commentary about how we’re changing the world that killing and eating one of the world’s most beautiful fish – as long as they’re from the introduced populations now crowding the Caribbean or Atlantic – actually helps the ocean.

To see lionfish and the scientists, fisherwomen, and chefs whose lives they’ve tangled, watch Saving the Oceanon PBS television, and on the Web.

Safina is founding president of Blue Ocean Institute at Stony Brook University, where he also co-chairs the University’s Center for Communicating Science. He has authored 6 books and roughly 200 scientific and popular publications, including features in The New York Times, and National Geographic and a new Foreword to Rachel Carson’s The Sea Around Us. He hosts Saving The Ocean on PBS television.